LYMPHATIC SYSTEM

Dr Rozzana Mohd Said

ORGANIZATION

Consists of:1. Lymph2. Lymphatic

vessels3. Lymphoid

tissues and organs

4. Lymphocytes + phagocytes + other cells

FUNCTIONS

Primary function:To produce, maintain and distribute lymphocytes for body defense mechanisms

Secondary function:1. To return fluid into the general circulation

so that normal blood volume is maintained2. To distribute hormones, nutrients and

waste products from tissues of origin to the general circulation

• The lymphatic system collects toxins in the body

• If this flow is impaired, the fluid becomes thick and toxic.

• The lymphatic system is filled with millions of one-way valves, which allows the lymph fluid to flow in only one direction - usually upward away from gravity.

The system

LYMPHATIC VESSELS

• small amount of interstitial fluid that remains is picked up by tiny vessels called lymph capillaries.

• lymph capillaries wall very porous

LYMPHATIC VESSELS

• lymph capillaries drain into still larger vessels that make up the lymphatic system.

• flow through the lymph vessels is quite slow

• Lymphatic vessels carry lymph, a colorless liquid, throughout the body. Along lymph vessels are small bean-shaped glandular nodules called lymph nodes.

LYMPHATIC VESSELS• Afferent lymphatic

vessels carry lymph into the nodes where waste products and some of the fluid are filtered out

• Efferent lymphatic vessels carry lymph out of the node to continue its return to the circulatory system.

BLOCKAGE OF THE LYMPH VESSELS

Elephantiasis. Elephantiasis is a condition of extreme edema that occurs when lymph vessels become blocked by filarial worms. Here the left leg is swollen with the fluids accumulated in the tissues as a result of the blockage.

LYMPHATIC CIRCULATION• All the lymph collected

from – the entire left side of

the body, – the digestive tract

and – the right side of the

lower part of the body– flows into a single

major vessel, the thoracic duct.

Drainage area

• The Left Drainage Area removes lymph from the:

• Left side of the head and neck

• Left arm and the left upper quadrant

• Lower trunk • Both legs

• The Right Drainage Area removes lymph from the:

• Right side of the head and neck

• Right arm • Upper right quadrant

of the body. • Lymph from this area

flows into the right lymphatic duct. This duct returns the lymph to the circulatory system by draining into the right subclavian vein.

LYMPH• Lymph originates as

blood plasma lost from the circulatory system, which leaks out into the surrounding tissues

• within the lymphatic system the fluid is called lymph, and has almost the same composition as the original interstitial fluid.

LYMPH• The production of lymph is

increased by 1. increased blood pressure in the

capillaries and/or 2. a decreased concentration of

plasma proteins (such as occurs in prolonged malnutrition).

The lymphatic system may be unable to handle the increased volume of lymph, and it may accumulate in the tissues and distend them. This condition is known as edema.

POSITION OF LYMPHATIC ORGANS IN THE BODY

• Tonsil: clusters of lymphatic tissues just under the mucous membranes that line the nose, mouth, and pharynx.

• Nasopharyngeal tonsils / adenoids: at the back of the nose, at the meet of the back of throat

LYMPHATIC ORGANS

LYMPHATIC ORGANS

• Peyer patch: lymphoid tissue on the visceral surface of the small intestine.

LYMPHOID ORGANS

• Spleen: it is similar to a lymph node in shape and structure but it is much larger

LYMPHOID ORGANS• Thymus: a

soft organ with two lobes that is located anterior to the ascending aorta and posterior to the sternum.

LYMPH NODES• Lymph nodes are

scattered throughout the lymphatic system– groin – armpits – abdomen and – neck.

• Lymph nodes also manufacture – antibodies and – lymphocytes

• These contain cavities - called sinuses - into which the lymph flows – The walls of the

sinuses are lined with phagocytic cells

– filtering mechanism – heavy infection -

"swollen glands".

STRUCTURE OF THE LYMPH

NODES

LYMPHOCYTES• A lymphocyte is a type of white

blood cell present in the blood • lymphocytes help provide a specific

response to attack the invading organisms

• Lymphocytes help to protect the body against tumors (tissues that grow more rapidly than normal)

• lymphocytes can also cause the rejection of tissues during organ transplants because they interpret these tissues as foreign invaders

LYMPHOCYTES• Lymphocytes are formed in

lymphatic tissue throughout the body • lymphatic tissue include the spleen,

thymus, tonsils, and lymph nodes • Lymphocytes are also made by fetal

stem cells and develop in the bone marrow – After the lymphocytes are formed, they

are released into the circulating blood.

LYMPHOCYTES• two types of

lymphocytes – T cells and B cells – differ in function

and the molecules that are on their surface

• 15% to 40% of white blood cells are lymphocytes

In general, the lymphatic system:

1. Drains fluid back into the general circulation

2. Filters lymph3. Fight infections